9.3.7.14 The (Plot Details) Drop Lines Tab

You can add drop lines to either axis in any 2D data plot type that incorporates plot symbols, and to any plane in 3D scatter and trajectory graphs.

2D Graph	3D Scatter, 2D/3D Ternary Graph

1 Direction Control for Drop Lines
2 Line Style Controls
- 2.1 Setting Drop Line Color
  - 2.1.1 Single Color for all drop lines
  - 2.1.2 Different Colors By Points
3 Drop To Controls
4 Arrow Controls
5 Show at Specified Points Only

Direction Control for Drop Lines

For 2D graph in cartesian coordinate, Horizontal or Vertical drop lines are optional.

For 2D ternary and 3D (including 3D Ternary) graph, drop lines Parallel to X/Y/Z Axis are optional.For 3D Scatter/Trajectory graph, Drop Lines tab is available on both Original and XY/ZX/YZ Projection level: On Original level, drop lines on all three directions(parallel to X/Y/Z axis) are optional; but on XY/ZX/YZ Projection level, only two directions along the axes of current panel are optional, such as on XY Projection level, you are only allowed to turn on the drop lines parallel to X and Y axis. For 3D Ternary graph, only drop lines parallel to vertical Z axis(Zh) is available. In contrast, all three directions are allowed to add drop lines for 2D Ternary graph.

Line Style Controls

Select the Horizontal/Vertical or Parallel to X/Y/Z Axis check boxes to display horizontal or vertical lines from each data point symbol to the bottom X or left Y axis. Then select the style, width and color for the drop-line with the Style, Width and Color drop-down lists.

Setting Drop Line Color

You can separately specify the color of the drop lines, using the Color Chooser just like that for the data plots.

Single Color for all drop lines

When you select Auto from the Color drop-down lists in the Single sub-tab, Origin uses the color selected from the Symbol Color or the Edge Color buttons on the (Plot Details) Symbol tab.

You can specify a desired color to apply it to all drop-lines at current direction. If you want to define and use a custom color for the drop lines, you can refer to this page.

Different Colors By Points

In the By Points sub-tab of Color Chooser, you can use a dataset to control the drop line color.

Just like the columns/bars in Bridge Chart, there is a special type of dataset color control for the drop lines:

Y Value: Plus-Minus: This option controls the drop line colors according to the condition that if the corresponding Y value is Positive, Negative. (Only available for Lollipop Plot)

For the drop line color, when Drop to Next Data Plot is selected, Y Value: Plus-Minus will show up in the By Points sub-tab of color chooser:

when Y value of next plot is bigger then this plot, then set the color of the drop line as the first color of color list
when Y value of next plot is smaller then this plot, then set the color of the drop line as second color of color list

Like Y Value: Plus-Minus-Total in bridge chart, selecting this method will also grey out the colors after the 2nd one of the color list.

Note: This special color control is also available for some other graph objects of other plot types:

For the border and fill color of Column plot, Y Value: Plus-Minus will show up in the By Points sub-tab of color chooser. Selecting it means:
- if Y value is bigger then custom additional line Y=, then use 1st color in the color list
- if Y value is smaller then custom additional line Y=, then use 2nd color.
For the symbol color(including symbol edge, symbol fill color) of scatter plot and line+symbol plot, when there is vertical or horizontal drop line(one direction only), and Drop To has not been set to Next Plot, Y Value: Plus-Minus will show up in the By Points sub-tab of color chooser. Selecting it means,
- if Y value is bigger then base line(axis or custom additional line), then use 1st color
- if Y value is smaller then base line, use 2nd color.

Drop To Controls

You can use this drop-down list to specify which line(axis line or additional line) or surface(axis panel or surface from 3D data) the current drop lines should be dropped to.

For 2D Scatter/Line graph in cartesian coordinate, four options are available under this drop-down list:

Auto: This item is selected by default to make drop lines drop to Left X and bottom X axis.
X/Y=Axis Begin: Make drop lines drop to the left Y Axis/bottom X axis which is at the position X/Y=Min.
X/Y=Axis End: Make drop lines drop to the right Y Axis/top X axis which is at the position X/Y=Max.
X/Y=Custom Additional Line:Make drop lines drop to the custom additional line at X/Y=custom value. If there is no additional line, drop lines will follow the Auto behaviors.
Next Data Plot: Make drop lines drop to the next plot at the same X values. This item in Vertical group will be selected by default for Lollipop Plot.

For 2D Ternary graph, two target axis lines are available under this drop-down list:

When drop lines Parallel to X Axis, you are allowed to select Y or X to specify which axis the drop lines should drop to.
When drop lines Parallel to Y Axis, you are allowed to select X or Z to specify which axis the drop lines should drop to.
When drop lines Parallel to Z Axis, you are allowed to select X or Y to specify which axis the drop lines should drop to.

For 3D Scatter/Trajectory graph, four options are available under this drop-down list:

Auto:This item is selected by default to make drop lines drop to X=Min/Y=Max/Z=Min plane.
X/Y/Z=Axis Begin Plane: Make drop lines drop to the YZ/XZ/XY panel which is at the position X/Y/Z=Min.
X/Y/Z=Axis End Plane: Make drop lines drop to the YZ/XZ/XY panel which is at the position X/Y/Z=Max.
Surface:Make drop lines drop to the surface which is created from 3D data. If there is no surface, drop lines will follow the Auto behaviors.

For 3D Ternary Scatter graph, only Parallel to Z Axis is available which can be used to add drop lines along vertical Z axis(Zh).

Arrow Controls

For 2D Scatter/Line graph in cartesian coordinate, you are allowed to add arrows at the end of the drop lines.

You can specify the Arrow Shape, Arrow Width and Arrow Length for the arrows. The unit of the arrow width and arrow length is points.

For the ternary and 3D graphs, Origin doesn't support to add arrows at the end of the drop lines.

Show at Specified Points Only

This control can be used to add drop lines at specific data points or at specific x values.

Here, five syntaxes are supported:

row indices separated by spaces, such as 1 3 5 show drop lines at specified row 1,3,5
start and end row indices with the number of skipped points, such as 2:0:5 shows 1 row and skip 5 rows, from 2nd row to the end row
X/Y values with space separators, but need add x= or y= before the values, such as x=3.5 7.8 show at specified X values(3.5 and 7.8), y=5.3 8.9 10.5 show at specified Y values(5.3, 8.9 and 10.5)
row indices stored in another column which can be selected in the drop-down list, such as [Book1]sheet2!col(A) show drop lines at specified rows, with row indices from this selected column
X/Y values stored in another column which can be selected in the drop-down list, but need add x= or y= before the range, such as x=[Book1]sheet2!col(A) show at specified X values, with X values from this selected column

Please note, when you are adding the drop lines by specifying the X/Y values, if the specified x/y values are not dropped on the data points, the interpolation will be performed to locate the specified X values at the connect lines between the nearest data points. And, only when the Line Connect had been set to Straight, the drop lines specified by X/Y values will work. See an example as below: